Makindo Medical Notes

⚠️ Acute hypotension is diagnosed when systemic blood pressure falls below levels sufficient to maintain organ perfusion. Traditionally invasive monitoring was used, but non-invasive methods are now preferred where possible.

📖 About Hypotension

• Hypotension = systemic blood pressure below the normal range.
• No strict threshold, but <90/60 mmHg is commonly considered hypotensive.

🧪 Physiology

• Blood Pressure = Cardiac Output × Total Peripheral Resistance
• MAP (Mean Arterial Pressure) = 2/3 Diastolic + 1/3 Systolic
• Cardiac Output = Stroke Volume × Heart Rate
• Target MAP for organ perfusion = ≥65 mmHg (sepsis / shock guidelines).

🚨 Causes of Hypotension

🩺 Clinical Features

• Light-headedness, dizziness, presyncope
• Syncope, blurred/darkened vision, tinnitus
• Cold, clammy peripheries; tachycardia (except neurogenic)
• Reduced urine output, confusion, drowsiness if severe

🔍 Investigations

• Bloods: FBC, U&E, LFT, clotting, lactate
• Group & cross-match if bleeding suspected
• ECG, troponin, echo for cardiogenic causes
• CXR, ABG, cultures (if sepsis)
• Amylase, cortisol, SynACTHen if adrenal insufficiency suspected
• D-dimer, CTPA if PE suspected

🛠️ Management Principles

• 🔄 Airway, Breathing, Circulation (ABC) approach
• 💧 IV fluids if hypovolaemia present
• 💉 Vasopressors (e.g. noradrenaline) if MAP <65 mmHg despite fluids
• 🩸 Blood transfusion if haemorrhage
• 🦠 Sepsis → IV antibiotics within 1h, source control
• 🌡️ Anaphylaxis → IM adrenaline first-line
• 🧪 Steroids in adrenal crisis / refractory septic shock

📚 References

• Hypotension Review – StatPearls
• NICE Sepsis Guidance
• Resus Council UK – Anaphylaxis Algorithm